Water is the most universal of solvents and though polar in its make up, it exhibits properties that indicate a sort of polymerizing link between its molecules similar to heavier organic non-polar compounds, another feature making it a perfect transport medium, as it is entirely able of dissolving molecules such as glucose.
While it exists on earth in all three basic states, solid, liquid, and gas, water's properties are often bizarre by most standards. For example liquid water contracts when cooled until it reaches a temperature of about 4 degrees Celsius where it reaches its maximum density. When this temperature is reached liquid water begins to expand, and even with a change in state to ice, water continues to expand, by reducing its density as its temperature decreases.
Water is also extremely useful due to its high specific heat capacity. It has an enormous ability to absorb and transmit energy. For example the amount of energy it would take to melt 1 kilogram of ice at zero degrees Celsius would be enough to lower the temperature of 1 kilogram of Aluminum over 570 degrees Celsius. While the amount of heat it would take to melt that kilogram of ice, heat it and boil away, 720 Calories, would be enough to raise that same amount of Aluminum to its melting point! This is why water is ideal as insulation or a heat dissipation source; it also means that large bodies of water are very stable in temperature, for instance the sea. This is odd because there is nothing in its chemical makeup or structure that justifies this ability to hold so much heat.
As water has a high specific heat capacity it is also an extremely effective coolant, as it also has a high latent heat of vaporization. For example mammals sweat a solution comprising mainly of water, to cool down, they do so because in order for the water to vaporize it must draw energy (heat energy) from its surroundings, in this case the animal, therefore cooling it down.
Water reacts with more substances than any other compound. It reacts physically with several compounds to add to their crystalline structure. Compounds like copper and magnesium sulfate are two examples of many compounds that almost always found in nature with water molecules physically attached to their crystalline structure. These types of compounds are often "dried out" or dehydrated and used to absorb water from their surroundings. Some of these compounds have water as such an important part of their structure that they will even extract all available moisture from the air. These compounds are natural dehumidifiers, dependent on water to complete their structure.
Water also reacts chemically with many substances, creating new substances or compounds. Dissolve Ammonia gas in water and the result is a powerful base, Ammonium Hydroxide. Dissolve Hydrogen Chloride gas in water and the result is a powerful acid, Hydrochloric Acid. These are but two of many examples of water combining with another compound to create a new substance. In some cases water's presence in abundance explains why some substances are not usually found. For example pure forms of two abundant and common elements on earth, almost never are found in nature. Sodium and Potassium, both metals in their pure form, are almost never found in nature because they react instantly and explosively when brought into contact with water. These are extreme examples but everyone knows that water aids in the rusting and corrosion of metals, Water acts as a catalyst for rust which is the combining of oxygen to metal.
Water is also a source of hydrogen and oxygen for chemical reactions. Many organic compounds get their oxygen and/or hydrogen from reactions with water. Alcohols, fatty acids, proteins, and many other organic compounds owe their existence to the reaction of organic molecules with water.
While water is used both chemically and physically, with both organic and inorganic substances, it has some characteristics that scientist still don't completely understand. Water molecules have a unique ability to be energized by microwave radiation, and at the same time make an excellent barrier to nuclear radiation. It absorbs neutrons in nuclear power plants, yet is easily heated by microwaves.
Water has excellent properties of cohesion, again due to its dipole nature, and the fact that the molecules or magnetically attracted to each other. An example of how this is used in the biological world is in the transpiration stream of plants, in witch the evaporation of water at the top of the plant (via the stomata) draws a column of water up the plant (in the xylem).
Water still has some surprises left. Due to the existence of heavy hydrogen atoms of deuterium and trinium, water is the primary source of the raw materials needed for hydrogen bombs. Water also is the ideal source of hydrogen for the creation of Plasma, and the possible development of controlled fusion reactions.
Water is a compound that we know so well yet know so little about. In its simple structure may be the key to understanding so much about the nature of chemical structures and reactions. A complete understanding of how and why the water molecule works may prove invaluable to our future development of new products and technologies.
